Around 1480, William White complained to the Chancellor that one John Fraunceis, a sanctuary man at the hospital of St Katherine by the Tower, had sued him in a court at St Katherine’s.
Fraunceis was in sanctuary for debt and perhaps his strategy for getting out of his money troubles was to use the jurisdictional independence of St Katherine’s to his advantage. St Katherine’s was one of the liberties in the London area; amongst the jurisdictional privileges St Katherine possessed was having its own courts, both temporal and ecclesiastical. (Unfortunately, records don’t survive.)
According to White, Fraunceis sued him in the steward’s court at St Katherine’s using a forged document recording a debt. Fraunceis assured his victory in the case, White said, because all the jurors were sanctuary men biased in his favour.
We don’t know much about sanctuary in St Katherine’s (it’s a bit surprising to me that there would be enough sanctuary men there to fill up a 12-man jury). I have records for seven men taking sanctuary there (all debtors) between 1467 and 1515.
In general St Katherine’s precinct was a bit shady in the later 15th century: located conveniently near the Tower garrison and the river, it had a thriving sex trade, as in general its inhabitants played with the jurisdictional immunities.
In August 1491, on the orders of Queen Elizabeth, the master of St. Katherine’s expelled 40 bawds and prostitutes from the precinct. This came up in a marriage case in the Consistory court of London, where one side’s witnesses discredited others who lived in St Katherine’s. (See also this article I wrote about the liberties in London, especially St Katherine’s.)
As usual with Chancery cases, we don’t know how this one ended, whether White was able to escape Fraunceis’s machinations, or whether Fraunceis won the day, perhaps justifiably (maybe it was White who was manipulatively avoiding his debts).
TNA, C 1/63/5. Top image – The precinct of St Katherine by the Tower. Source
Sanctuary Seekers in England, 1394-1557 
